Fluid treatment systems of the kind mentioned at the outset are known from WO 2001/017663 of the applicant. As evident from the FIG. 1 representing this prior art, the known fluid treatment system 1′ encompasses a tubular channel 2′, depicted on FIG. 1 in section, transverse to its longitudinal axis, and a plurality of migrating bed reactor modules 3′ arranged in tandem inside the tubular channel 2′. A feed channel 4′ situated below for untreated fluid along with a discharge channel 5′ lying over it run parallel to a lateral wall of the tubular channel 2′. The fluid to be treated flows via a laterally situated, if necessary sealable, feed window 6′ in a gas distribution room 12′ under a feed floor 8′ into each reactor module. By way of the feed floor 8′ known from EP 0257654 B1, the fluid to be treated arrives in a horizontally extended bulk bed 9′ of roughly uniform height, which consists of adsorptively or absorptively or catalytically active bulk particles, for example. Located above the bulk bed 9′ under the tubular channel cover 10′ is a continuous charging channel 11′, in which the treated fluid can accumulate before exiting through lateral, if necessary sealable, discharge windows 7′ of the migrating bed reactor module 3′ and removed from the fluid treatment system 1′ via the discharge channel 5′.
In order to gradually replenish the bulk material of the bulk bed 9′, consumed bulk material is occasionally removed at the lower end, and fresh bulk material is again supplied at the top end, so that the bed height remains constant. The incremental removal of bulk material takes place in a known manner via the feed floor 8′, the bulk material discharge pipes 13′ of which can be opened and then closed again via a bulk material discharge device 15′ known in the art. To this end, at least one discharge finger 15B′ each above a horizontal baffle plate 15A′ can be moved horizontally through the gap space between the baffle plate 15A′ and accompanying bulk material discharge pipes 13′ up to the lateral edges 15C′ of the baffle plate 15A′. As a result, the bulk material is discarded from the baffle plate, and a corresponding amount of bulk material slides down from above out of each bulk material discharge tub 13′. Removed bulk material can be discharged by means of a bulk material discharge wagon 16′ or a conveyor belt running along the tubular channel 2′.
In order to be able to supply an additional, equally large quantity of fresh bulk material for sustaining the bed height at the same time the bulk material is being removed, a charging wagon 19′ is provided that uses a traveling mechanism 18′ to traverse along the tubular channel 2′ within the latter. On FIG. 1, the charging wagon 19′ is just above the migrating bed reactor module. The charging wagon 19′ is tub-shaped, and provided with a plurality of discharge funnels 20′ arranged in the form of a grid, which pass over into bulk material outlet pipes 14′ at their lower end. Located below the lower mouths 21′ of the bulk material outlet pipes 14′ is a horizontally extending dust plate, which serves as a bulk material valve 23′, and for this purpose is perforated with holes in the respective positions of the mouth ends of the bulk material outlet pipes. The dust plate can be shifted horizontally around roughly one width of a hole, so that when in its second sliding position, it seals the mouth ends of the bulk material outlet pipes 14′. This makes it possible for the charging wagon 19′ to traverse each of the migrating bed reactor modules 3′ arranged in tandem in the tubular channel 2′, so as to there effect an exchange of bulk material. If the charging wagon 19′ is now moved along the charging channel 11′, the dust plate interrupts the flow of fluid at the upper end of the bulk bed 9′ over which the charging wagon 19′ is traveling at the time, and the dust plate grinds over the tips of the bulk material cones that form as refilling takes place at the upper limit of the bulk bed 9′.
The uniformity with which the bulk material migrates through the bulk beds is of great importance for the technical effect and efficiency of such a counter-current fluid treatment procedure. For this reason, special discharge devices 15′ are used under each bulk bed, which withdraw practically the same quantity of bulk material per outlet from each of the most often numerous bulk material removal pipes cyclically in each working stroke. The bulk material discharge devices used with great success for this purpose are known from EP 0 357 653 B1. In this known bulk material discharge device, a striated, continuous baffle surface with a constant width in the form of a transverse leg of a U or T-carrier is arranged underneath a series of adjacently arranged mouth openings of the bulk material removal pipes. A finger-shaped rod 15B′ arranged parallel to the series of pipes, and hence also parallel to the oblong baffle surface, fits undersized between the baffle surface and tubular mouths, and can be moved by a drive cyclically and reversibly from its faces between the lateral edges 15C′ of the baffle surface, transversely to their longitudinal extension. In each of these movements, bulk material backed up under the pipe mouth on the baffle surface is thrown over the lateral edge of the baffle surface into a collection tank situated below. The latter can be a funnel arrangement separate for each migrating bed reactor module 9′, a bulk material discharge wagon 16′, which travels in a bulk material discharge channel through a plurality of bulk material reactor modules, or also a conveyor belt. The long-term functional capacity of these discharge devices has for 20 years served as a guarantee for the flawless function of generic fluid treatment systems. Material properties limit the length of these discharge devices, so that an independently powered discharge device is normally used for each bulk bed (migrating bed reactor module).